LOS ANGELES — From the Hollywood mansion that serves as the fictional home of HBO's Entourage, you can see the series depicted on a real billboard.
The comedy about rising movie star Vincent Chase (Adrian Grenier) and his New York boyhood buddies kicks off its third season June 11 (10 ET/PT). And as the show's visibility has grown, particularly in the entertainment world, the sitcom seems less a case of art imitating life than paralleling it — and even influencing it.

In an episode last year, Bono gave a birthday shout-out to actor Johnny "Drama" Chase (Kevin Dillon), Vince's far-less-famous brother, at an actual U2 concert. Talent agents have been known to discuss the make-believe antics of Entourage agent Ari Gold (Jeremy Piven) even as some field more job offers for the real-life actors. And location shoots — ranging from Beverly Hills' Rodeo Drive to a West Hollywood coffee shop — have become more likely to be interrupted by passersby who call out to the characters.

Jerry Ferrara, who plays Turtle, the Brooklyn-to-the-core driver, says that during a recent shoot at Las Vegas' Hard Rock Hotel & Casino, "all 250 people started screaming 'Turtle.' I felt like I was dreaming."

With Sex and the City gone, Entourage is HBO's next great comedy hope. The critically praised series' audience rose as last season ended. "We are thrilled with the way the show has been growing creatively," HBO entertainment president Carolyn Strauss says.

Nevertheless, Entourage has far to go to fill Sex's Manolo Blahniks in the ratings. Its largest audiences have yet to hit 3 million viewers; Sex regularly doubled that number, and its 2004 finale topped 10 million.

But Strauss says the show is generating buzz both inside and outside the entertainment business, important for a subscriber-based network. "It's that kind of show that seems in the offseason to pick up momentum and collect new viewers," she says.

Band of brothers

Entourage, based on executive producer Mark Wahlberg's experiences as a star, already is a survivor in a sea of sunken behind-the-scenes takes on Hollywood, including HBO's The Comeback. Perhaps that's because, as creator Doug Ellin contends, Entourage is more about the relationships among a group of likable guys than showbiz minutiae. "It's not a Hollywood show. It's a show about friendship," he says. "I watched Diner 400 times. That was the tone I wanted."

But the real Hollywood always figures into the calculation. When deciding how to handle the box-office fate of Vince's film, Aquaman, Ellin had to consider Titanic director James Cameron, who plays himself as Aquaman's director. "You don't want to make (Cameron) have a bad movie," he says.

The season explores how the guys deal with success' twists and turns. Relationships evolve, including the rivalry between Ari and Vince's smart but green manager, Eric (Kevin Connolly). And viewers will see how Ari relates to his wife and daughter at home.

James Woods plays an over-the-top media image of himself in the first episode, joining numerous celebs who have portrayed (and occasionally parodied) themselves on the show, including Wahlberg, Jessica Alba, Mandy Moore, Scarlett Johansson, Bob Saget, Gary Busey, Hugh Hefner and the rapper Saigon.

Entourage also serves as a travelogue of chi-chi LA, at the Malibu beachfront, a Lakers game, the Playboy Mansion, the babe-infused Urth Caffe and numerous nightspots.

"There was a fear in the beginning that we'd be too inside," says Piven, whose Ari is rebuilding his career after being booted from his agency. But "people have displayed a hunger for the backstage life of artists. We're being as specific as we can with that world. People within (the business) recognize it. Outside of it, they're curious about it."

Hollywood, a big boy's toy box full of snazzy sports cars, never-ending parties and a sugar high of arm candy, gives the series a fantasy appeal that even wows the cast members. Grenier (who also can be seen in The Devil Wears Prada June 30) says he and his castmates don't have the time or inclination to party as relentlessly as their alter egos do. "Even I watch the show ... and live vicariously through the characters," he says.

Connolly, whose Eric is usually referred to as E, notes the show doesn't focus on Vince's work on set. "Who does live that lifestyle? The guys wake up, eat breakfast, hit golf balls, jump in a $150,000 car, eat a nice dinner, go to a club, grab the hottest girls and bring them back for a party," he says.

Drama weaves into the comedy, but Entourage isn't a satire and doesn't go heavily into the dark side of showbiz. "I think it nails the fun part of Hollywood," he says.

Although the actors may not club as much as their characters, they are hardly strangers to Hollywood nightlife. Connolly dates socialite Nicky Hilton and has been mentioned in celebrity news accounts hitting the town with Leonardo DiCaprio and Tobey Maguire.

And they live it up with one another. "Whatever you see on television, how much fun it looks like we're having and how good we get along, times that by 100 when the cameras aren't rolling," says Ferrara, who attended Dillon's recent Las Vegas wedding, as did Connolly.

Doors are opening for cast

The main nightlife planned this Friday before the Memorial Day weekend is a long day-into-night shoot. The four buddies are doing a kitchen breakfast scene in the rented Mediterranean-style manor that snakes up a hillside, offering views from Hollywood to the Pacific. (Twenty episodes are being filmed, 12 of which will run this summer.)

The estate is worth millions, but its décor is hardly a candidate for Architectural Digest. "The main criteria was that it shouldn't feel overdesigned. This suits them more. They're into comfort, not presentation of lifestyle," says director Julian Farino, a filmmaker with a documentary background who pushed for filming in the house's interior rooms rather than creating sets on a soundstage.

Shooting here "makes it so much more real," says Dillon, seated on a patio that overlooks a pool and offers a panorama of the city. For viewers, "it feels like you're there."

For Dillon — brother of actor Matt Dillon —Entourage got a bit too real when he broke his arm during a recent basketball scene. He had a plate and 10 screws put in, and was back two days later for a photo shoot, sans sling. "I'll probably look totally out of it."

All the other breaks have been positive. Grenier says Entourage opened the door to Prada. Dillon and Piven, who earned an Emmy nomination last year, also say it has helped them get roles, Dillon in Poseidon, Piven in Keeping Up with the Steins and the upcoming Smoking Aces. "Now, I'm getting their attention" for meatier roles, Piven says.

The higher profile helps around town, too. "I used to be the guy trying to tip the (nightclub) doorman 10 bucks to get in and having him laugh at me," Ferrara says. "Now I go into a club and I don't have to bring a wallet. The parallels (with the show) are unbelievable."

And helpful. As Grenier deals with his fame, "I'm learning from Vince. He's teaching me all about the do's and don't's of celebrity."